ISOPODA 



379 



Fig. 605 — Oniscus 

 asellus (Paulmeier). 



0. asellus L. (Fig-. 605). Length IG mm.; width 8 mm.; color deep 

 slate, spotted with white, and white along the lateral edges: eastern and 

 central states; Europe; common under bark of fallen 

 trees, logs, stones, etc. 



2. Philoscia Latreille. Second antennae ends 

 with 3 short segments; side of head not extended 

 under the eyes ; abdomen abruptly narrower than the 

 thorax: 7 American species. 



P. vittata Say (Fig. 606). Length 8 mm.; width 

 4 mm.; color usually dark brown with 2 darker 

 median stripes : along the seashore from New Jersey 

 to Cape Cod, under stones and boards above high tide. 



3. Cylisticus Schnitzler. Body rather elongate, 

 smooth, very convex, and able to be rolled into a 

 ball; head with lateral lobes; second antennae long, 



ending with 2 short segments; uropods long: 1 Amer- 

 ican species. 



C. convexus (DeGeer) (Fig. 607). Length 12 mm.; 

 width 5 mm.; color brown or dark gray, spotted Avith 

 white: eastern and central states; Europe; under logs 

 and stones in rather dry places. 



4. PoRCELLio Latreille. Body oval, flattened; head 

 with lateral lobes; second antennae long, ending with 2 

 short segments; uropods long; respiratory plates of. 

 either the first 2 or all 5 pairs of pleopods provided 

 with tracheae: 6 American species. 

 P. rathkei Brandt. Body granulate, 10 mm.- long and 5 mm. wide, 

 yellowish-brown in color with numerous black blotches and two lateral 



Fig. G06 



PhiloHcia vittata 



(Harger). 



Fig. 607 Fig. 608 Fig. 609 



Fig. 607 — Cylisticus convexus (raulmeiei*). Fig. 608 — Porcellio scahcr (Paulmeier). 

 Fig. 609 — Metoponorthus pruinosus (Paulmeier). 



and usually a median light stripe: eastern and central states; Europe; 

 common under boards, stones, etc. 



